In recent years, decreased prices and increased processing capability have resulted in a dramatic increase in the use of portable computing devices. Consumers are attracted to portable computing devices because, among other things, they are lightweight and allow users to perform computing tasks outside of the confines of an office. Portable computing devices are utilized in many places where computing was not previously possible (e.g., planes, automobiles, park benches, at home on a couch, etc.). The versatility of a portable computing device, however, can be limited by insufficient lighting conditions. When there is an insufficient amount of available ambient light, a user may have difficulty seeing the keyboard and may therefore find it difficult to accurately and efficiently operate the portable computing device.
To provide ambient light, some laptop computers provide task lights mounted to the top surface of the display, which is attached to the keyboard using a hinge. In this configuration, the area of illumination provided by the task lights changes when a user moves the display relative to the keyboard. When the display is tilted beyond a certain angle, the task light may fail to illuminate the keyboard at all. Tilting the display may also cause a direct light source to be visible to the user or bystanders in the vicinity. This visible direct light source can be a distraction and annoyance.
Other laptop computers illuminate the keyboard by directing a portion of light from the display panel to the keyboard. Because the keyboard illuminator and display panel share a common light source, if a user were to reduce the display brightness in a low-light environment, the light directed to the keyboard would correspondingly be reduced. When a user adjusts one, the other is necessarily adjusted as well. Additionally, this configuration may reduce display brightness, because energy is diverted from the display to the keyboard illuminators.
Certain other keyboard illumination techniques rely on moving parts, such as shutters or doors, to hide the task light when it is not needed. In such systems, the moving parts are subject to mechanical failure.
Advantages of these and other embodiments will become apparent from the following detailed description, which taken in conjunction with the accompanying drawings, describe by way of example—and not limitation—principles of various exemplary embodiments.